James m



(No Model.)

J. M. CARPENTER.

. SCREW PLATE.

Patented D60. 25, 1883.

24 L ======E A m W FIEUE.

WITNESSES- N. PETERS. Phuln-Lilhognphnr. Wafllinglnn, u. c,

NlTED STATES PATENT OFFICE.

JAMES M. CARPENTER, OF PAWTUOKET, RHODE ISLAND.

SCREW-PLATE.

SPECIFICATION forming part of Letters Patent No. 290,857, dated December 25, 1883. Application filed J one 9, 1883. (N0 model.)

To all whom it may concern:

Be it known that 1, JAMES M. CARPENTER, of Pawtucket, in the county of Providence and State of Rhode Island, have invented a new and useful Improvement in Screw-Plates; and I hereby declare the following specification, taken in connection with the accompanying drawings, forming a part of the same, to be a description thereof.

This invention consists in a screw-plate the dies of which are held in position by a removable sliding yoke-piece, which is inserted into the screw-plate through a slot in the edge or side thereof, passes through grooves in opposite sides of the dies, and occupies slots in the screw-plate which support the yoke-piece, as will hereinafter appear.

Referring to the drawings, Figure 1 represents a face view of a screw-plate embodying the invention. Fig. 2 shows a portion of the same, with the central part in section, the yokepiece being shown in position by dotted lines and the dies being removed. Fig. 3 represents a transverse section on line a; x of Fig. 1. Fig. 4 shows the yokepiece in perspective.

A is the frame of the screw-plate, which is provided with a central mortise, A, in which the dies B B are mounted. As indicated by dotted lines in Fig. 1 and as shown at Fig. 3, the dies B have grooves 12 in their opposite edges to receive the legs of the yoke-piece O, which secures the dies in position. To receive the yoke-piece, the frame of the screwplate is provided with slots or holes a a a, as shown at Fig. 2, the slot or hole a being occupied by the head of the yoke-piece O and the slots or holes a by the extremities of the legs thereof when the yoke-piece is in place, as indicated by dotted lines. The dies are secured in position by placing them in the mortise A, then inserting the yoke-piece 0 through the slot a, passing its legs through the grooves in the edges of the dies and pushing it home, thereby causing the extremities of the legs to occupy the slots at a, as indicated in Fig. 1, and hold the dies securely in the mortise A.

As a guard against the yoke-piece becoming accidentally detached, the screw-plate may be provided with a thumb-screw, D, to engage a notch, d, in the side of the yoke-piece; or other suitable means may be employed to lock the yoke in position.

As shown in Letters Patent of the United States No. 178,270, issued to me June 6, 1876, a yoke-piece or supplemental frame has heretofcre been employed for mounting the dies in the mortise in the frame of the screw-plate; but in order to hold the dies in position the upper one was provided with a cavity to receive the clamp or gage-screw. This cavity in the die renders it more liable to warp in hardening and quite liable to break during use, and when the screw is sufficiently with drawn the dies and yoke-piece are liable to fall out of the frame of the plate.

My present invention is an improvement upon the screw-plate shown in said patent, in that the upper die is not weakened by the presence of a cavity to receive the clamp or gagescrew E, and the dies and yoke-piece will be retained in the frame A regardless of the position of said screw.

\Vhat I claim, anddesire to secure by Letters Patent, is

1. The combination, substantially as hereinbefore set forth, of the frame A, having slots or holes a a a, the dies B, having grooved edges, and the sliding yoke-piece 0, adapted to hold the dies in the frame.

2. The combination, substantially as hereinbefore set forth, of the frame A, having slot-s or holes a a a, the dies 13, having grooved edges, the sliding yoke-piece 0, adapted to hold the dies in the frame, and suitable means, as described, for locking said yoke-piece in position in said slots or holes.

JAMES M. CARPENTER.

\Vitnesses:

EDSON SALISBURY JONES, OSCAR LAPHAM. 

